Synthetic polymeric sewing threads packages



United States Patent Ofiice 3,217,989 Patented Nov. 16, 1965 3,217,989SYNTHETIC POLYMERIC SEWING THREADS PACKAGES Hanus Peter Vogel, London,England, assignor to Sewing Silks Limited, Greenford, 'Middlesex,England, a company of'the United Kingdom No Drawing. Filed June 11,1962, Ser. No. 201,266 Claims priority, application Great Britain, July13, 1961, 25,460/ 61 13 Claims. (Cl. 242-18) This invention relates topackaged sewing threads made wholly or partially of continuous filamentsof synthetic polymeric materials, for example polyamide fibres such asnylon, polyester fibres such as that sold under the registered trademarkDacron, or acrylic fibres.

It is the object of the invention to provide an improved package ofsynthetic filament sewing threads which is stable. The synthetic threadswith which the present invention is concerned are, in general, somewhatspringy or lively, and this springiness in association with thecharacteristic slippery surfaces of the threads makes them difficult tospool, as for a lock stitch sewing machine, since the thread tends tofall away from the supply cop or other package while being wound andgets trapped beneath it. The springi-ness of the tread further inducessnarling during winding off, sewing, and general handling. In addition,when a package of thread is partially used it generally exhibits atendency to collapse owing to the slippery nature of the surface of thethreads inhibiting cohes ion between the coils of the thread in contactone with another.

The snarling of the thread can be overcome to some extent by balancingthe thread, i.e., by forming the threads with both S and Z twists sothat there is no tendency for the thread to untwist itself in eitherdirection when it is in an untensioned state. By the practise of thepresent invention, it is possible to produce a package of deadunbalanced thread which is swisted in one direction only. Such a threadcan be constructed from coarser raw materials than those necessary forbalanced threads. For example, instead ofconstructing a thread of Dacron40 denier folded three ends=120 denier, a single 125 denier hightenacity Dacron thread can be used. In the same way a 210 denier nylonthread can be constructed from a single end of high tenacity nyloninstead of three ends 70 denier medium tenacity.

In accordance with the invention, a method of producing a wound packageof sewing thread so that it should be capable of being unwound'in asubstantially untensioned state without twisting on itself, and in whichthe thread is wholly or partially made of continuous filaments of asynthetic polymeric material, comprises the steps of coating the threadwith a solution or dispersion of an organic compound having selfadherent properties (as hereinafter defined), drying the coating toremove the solvent or dispersant, and winding the thread to produce athread package, the coating step and the drying step being carried outwhile no stretch is imparted to the thread, and the drying step beingcarried out before, during, or after the winding step.

The expression self adherent as used in this specification is to beunderstood to mean that a thread provided with a coating having suchproperties, and when wound in superimposed coils, is slightly adherentto itself to a degree similar to that normally exhibited by a staplefibre thread, but the thread does not exhibit any tacky characteristics.

A wide variety of substances may be employed for the coating compounds,including both curable and noncurable compounds. If a curable compoundis employed, the compound may be cured before, during or after thewinding step. However, certain curable compounds are found to exhibitthe required self adherent properties when left in an uncured state, andsuch compounds may be usefully employed in the practise of thisinvention.

Among the curable compounds which may be advantageously employed in thepractise of the invention are heat curable compounds, for example nylon66 (as sold under this trademark by E. I. du Pont de Nemours & Co.) inwhich some of the amide hydrogen atoms are replaced with methyl methoxygroups and certain thermo-setting acrylics. Examples of chemicallycurable compounds are acrylic polymers and copolymers cross-linked withan amino resin. Examples of non-curable compounds are polyvinyl acetate,and naturally occurring compounds such as shellac and certain naturalgums, e.g.., gum kauri.

The coating compound is in the form of a simple solution or dispersionof the organic compound in a solvent or dispersant, e.g., in alcohol,containing substantially no other solid particles in suspension.

The strength of the solution or dispersion may vary widely but ispreferably between 3 and by weight. For example when using a coatingcompound consisting of nylon 66 in which some of amide hydrogen atomsare replaced by methyl methoxy groups, a 5% solution or dispersion wouldnormally be used, but higher percentages such as 10%, or even 20%. canbe employed depending upon the thickness of the thread which couldeither be a single or folded thread, depending upon the purpose forwhich it is required.

The coating process may be carried out in any convenient way known inthe art. For example, the thread to be coated may be led through a bathof the solution or dispersion of the coating compound, the excess beingremoved by wipers, and the thread so coated dried at a moderatetemperature in a drying chamber. Alternatively the thread may be driedas it is wound upon a spool to form the final package. If a curablecompound is employed, and a curing step is necessary to produce therequired self adherent characteristics, the curing step may be performedby heat treatment, or by passing the thread through a bath of a curingagent according to the type of cure necessary, after the thread has beendried.

The invention is illustrated by the following examples.

Example 1 Nylon yarn of 210 denier twisted to thread 17 turns Z, heatstretched and stabilised was treated on a re-drawing frame by running itthrough a suitably constructed bath. The bath was made up of 15 grams ofnylon 66 in which some of the amide hydrogen atoms are replaced bymethyl methoxy groups dissolved in a mixture of 400 cc. of methylalcohol, 3.7 grams of citric acid and 100 cc. water The final woundpackage was partially cured at C. for twenty minutes in a conventionalvacuum steam unit. The package had, in this way, thread to threadadhesion, preventing the thread from falling off the package and alsoensuring that the thread remained under tension due to the adhesion whenbeing drawn off for eitherspool winding or sewing. The usual liveliness,experiments indicate, was successfully eliminated.

Example 2 Dacron yarn of 250 denier twisted to thread, 12 turns per inchZ, heat stretched and stabilised, was run through a bath containing 20gms. of nylon 66 in which some of the amide hydrogen atoms are replacedwith methyl methoxy groups dissolved in a mixture of 400 cc. of methylalcohol and cc. of water to which was added 1 gm. of citric acid as acatalyst. A doctor blade was used to remove surplus coating and thethread was wound onto a suitable package. The package was then placed inan oven at approximately 80 C. for 1 hr. to evaporate the solvent. Thethread Was wound onto the final package and was cured by placing in anoven at 120 C. for 30 minutes.

Example 3 Dacron yarn of 125 denier, twisted to thread turns per inch Z,heat-stretched and stabilised, was passed over a roller revolving in atrough containing an aqueous dispersion of polyvinyl acetate. The threadwas then passed over an infra-red heater and wound onto a suitablepackage. The thread on the package, although not sensibly tacky, wasfound to exhibit self-adhesion. Increased thread to thread adhesion wasobtained by placing the final package in an oven at 120 C. for 30minutes and then transferring to a suitably constructed cooling chamber.

Example 4 A 70 denier nylon yarn, twisted to thread 8 turns per inch S,heat stretched and stabilised, was run through a bath of the solutiondescribed in Example 2, passed several times over an infrared heater inorder to evaporate the solvent and cure the coating and was wound onto asuitable package. It was subsequently wound onto cocoon shaped shuttlesfor use on multi-needle quilting machines. A further treatment ofminutes in a vacuum steam unit was found to increase the thread tothread adhesion.

; Example 5 Dacron yarn, 125 denier, twisted 15 turns per inch Z, heatstretched and stabilised, was passed through a coating solution of 12percent by weight of gum kauri dissolved in a mixture of methylatedspirit and xylene and wound on to a drum. The thread was then allowed todry at ambient temperature until substantially all the solvent hadevaporated and then Wound to form a thread package. The thread packagethus formed, when used in a domestic sewing machine, ran off withoutsnarling and without the package collapsing by the coils of the packageslipping over each other.

Example 6 Dacron yarn, 250 denier, twisted 12 turns per inch Z, heatstretched and stabilised, was run over a roller revolving in a troughcontaining 600 grams of a reactive acrylic emulsion, 90 grams of anamino resin and sufficient ammonia to raise the pH of the mixture to 8.The thread was then wound into package form and allowed to stand at roomtemperature for a period of 24 hours.

What I claim is:

1. A wound package of sewing thread containing continuous filaments of asynthetic polymeric material characterized in that the thread isprovided with a non-tacky coating and the coatings of adjacent coils onthe package are directly and lightly adhered together to a degreesubstantially similar to that normally exhibited by a staple fiberthread.

2. A wound package as claimed in claim 1 wherein the thread is twistedin one direction only.

3. A wound package as claimed in claim 1 wherein the coating is of acured material selected from the group consisting of modified nylon andacrylic polymers.

4. A wound package as claimed in claim 1 wherein the coating is of amaterial selected from the group consisting of polyvinyl acetate,shellac and natural gums.

5. A wound package as claimed in claim 1 wherein the synthetic polymericmaterial is selected from the group consisting of polyamides, polyestersand acrylic compounds.

6. A method of producing a wound package of sewing thread capable ofbeing unwound in a substantially untensioned state without twisting onitself, and in which the thread is at least partially made of continuousfilaments of a synthetic polymeric material, comprising the steps ofcoating the thread with a liquid containing an organic compound havingthe property of self-adherence upon being dried, winding the thread toproduce a Wound package, and completely drying the coating of each coilafter such coil is on the wound package so as to cause adjacent coils ofcoated thread to adhere directly and lightly together. I

7. A method as claimed in claim 6 wherein the coating is partially driedbefore the winding of the thread.

8. A method as claimed in claim 6 wherein the synthetic polymericmaterial is selected from. the group consisting of polyamides,polyesters and acrylic compounds.

9. A method as claimed in claim 6 wherein said organic compound isselected from the group consisting of polyvinyl acetate, shellac andnatural gums.

10. A method of producing a wound package of sew-v ing thread capable ofbeing unwound in a substantially untensioned state Wltl'lOU't twistingon itself, and in which the thread is at least partially made ofcontinuous filaments of a synthetic polymeric material, comprising thesteps of coating the thread with a liquid composition containing acurable organic compound having the property of self-adherence uponbeing dried and cured, Winding the thread to produce a wound package,and curing the coating on the wound thread.

11. A method as claimed in claim 10 wherein the synthetic polymericmaterial is selected from the group consisting of polyamides, polyestersand acrylic compounds.

12. A method as claimed in claim 10 wherein said organic compound isselected from the group consisting of modified nylon and acrylicpolymers.

13. A method as claimed in claim 10 wherein the coating is partiallydried and cured before the winding of the thread.

References Cited by the Examiner UNITED STATES PATENTS 2,934,126 4/1960Wilson 57-140 3,019,132 1/1962 Gabler 117138.8 3,063,870 11/1962 Wakeman117-1388 3,064,911 11/1962 Truitt et a1 242-18 FOREIGN PATENTS 760,83711/1956 Great Britain. 821,266 10/1959 Great Britain.

WILLIAM D. MARTIN, Primary Examiner.

RICHARD D. NEVIUS, Examiner.

1. A WOUND PACKAGE OF SEWING THREAD CONTAINING CONTINUOUS FILAMENTS OF ASYNTHETIC POLYMERIC MATERIAL CHARACTERIZED IN THAT THE THREAD ISPROVIDED WITH A NON-TACKY COATING AND THE COATINGS OF ADJACENT COILS ONTHE PACKAGE ARE DIRECTLY AND LIGHTLY ADHERED TOGETHER TO A DEGREESUBSTANTIALLY SIMILAR TO THAT NORMALLY EXHIBITED BY A STAPLE FIBERTHREAD.